We define Weyl fermions on a finite lattice in such a way that in the
path integral the action is gauge invariant but the functional measure
is not. Two variants of such a formulation are tested in the perturba
tive calculation of the fermion determinant in the chiral Schwinger mo
del. We find that one of these variants ensures restoring the gauge in
variance of the nonanomalous part of the determinant in the continuum
limit. A 'perfect' perturbative regularization of the chiral fermions
is briefly discussed.